Optical fibers of priorly known optical cables have been susceptible to increases in attenuation because of mechanical and thermal stress. In an endeavor to avoid such stress optical fiber cables have been developed that include a plurality of ribbon-type light conductor units, each containing a plurality of optical fibers sandwiched between fiberglass-reinforced tapes. By having such tapes bonded to each other and to the plurality of optical fibers contained therebetween, the optical fibers cannot freely move, thus minimizing mechanical stress. Such fiberglass-reinforced tapes preferably have a coefficient of thermal expansion comparable to that of the optical fibers, and a tensile strength that permits a considerable amount of tensile stress to be absorbed by the tapes before elongation.
In the manufacture of ribbon-type light conductor units, an efficient in line connecting method is an imperative for the fabrication of extended lengths of such units. More specificially, there is a need to efficiently interconnect each of the optical fibers of a first such unit to a corresponding optical fiber of a second such unit so as to provide a continuous light transmission path of minimal attenuation through the interconnected optical fibers.
Previously, optical fibers have been welded at their end faces to the end faces of other optical fibers by the method of individually welding each pair of optical fibers. To avoid increases in light attenuation end faces of the optical fibers were formed to have plane surfaces. Cutting mechanisms for achieving a plane surface at the end face of an optical fiber are priorly known. Such mechanisms were employed in the manner of scratching an outer surface of the optical fiber with a cutting tool, and then applying a pulling force to the optical fiber to cause a separation or break at the scratch location.